Due to the technical benefit that a local area radio network extends the coverage area of a radio system and facilitates easy access of a user equipment to a core network, LTE radio systems have kept focusing on developments of the local area radio networks (also known as LTE-LANs for short) consisted of for example picocells or femtocells (also known as home-eNB cells) that operate in licensed spectra. To improve use-efficiency of the finite and increasingly crowded spectrum and decrease spectral costs, a few approaches for shared use of the spectrum have been recommended or applied, which for example include “ASA” as jointly recommended by Nokia and Qualcomm and use of license-exempt spectra such as a TV white space spectrum. For a better understanding of the LTE-LAN and its spectral usage involving a license-exempt spectrum, discussion will be made under a scenario as illustrated in FIG. 1.
FIG. 1 exemplarily illustrates a scenario 100 including a LTE-LAN network and a TV network. As illustrated in FIG. 1, the LTE-LAN network includes an LTE-LAN BS, e.g., FBS or PBS, and LTE-LAN UEs 1 and 2, e.g., FUEs or PUEs; the TV network includes a TV Tower and TV Ues 1 and 2. In a conventional communication, the LTE-LAN Ues 1 and 2 may communicate with the LTE-LAN BS or with each other via the LTE-LAN BS only in a licensed spectrum rather than in an unlicensed spectrum as licensed to and employed by the TV network. Therefore, it is convenient for network operators to manage and maintain such an LTE-LAN network, and no or only a little attention should be paid to interference from other unlicensed systems.
However, to better use-efficiency of radio spectra and decrease spectral costs, LTE-LAN Ues 1 and 2 should, as appropriate, also use the TV white space spectrum as unused by the TV network. To minimize the interference to the licensed users (e.g., TV Ues 1 and 2) in the TV licensed spectrum, the LTE-LAN Ues 1 and 2 may need to perform precise or sometimes even complicated spectrum sensing first, and then determine, by taking the interference into account, whether they are allowed to communicate in the TV white space spectrum. In other words, the LTE-LAN Ues 1 and 2 are qualified for using the TV white space spectrum on the condition that they cause no interference to the TV Ues 1 and 2.